XI: s-block Flashcards
What is polarising power?
[Ionic charge]/[(ionic radius)^2]
Which alkali metal ion has highest hydration energy?
Li
What is the colour of the flame that Lithium imparts to Bunsen burner?
Red
What is the colour of the flame that Sodium imparts to Bunsen burner?
Golden yellow
What is the colour of the flame that potassium imparts to Bunsen burner?
Pale violet
What is the colour of the flame that Rubidium imparts to Bunsen burner?
Reddish violet
What is the colour of the flame that Cesium imparts to Bunsen burner?
Sky blue
Which is the lightest metal?
Lithium
Density decreases along the period. True/false?
False. It increases along a period
Melting point decreases down the group. True/false?
True
Which is more reactive- lithium or cesium?
Cesium
The compound forms of alkali metals are diamagnetic. True
True
Does the stability of alkali hydrides decrease down the group?
Yes
NaH + H2O ————->
NaOh + H2
Na2O2 + H2O ————–>
NaOH + H2O2
KO2+H2O————>
KOH + H2O2 + O2
Which alkali halide is not freely soluble in water?
Lithium fluoride
Why does caesium iodide have low solubility in water?
Because of the small hydration energy
Is blue coloured solution of alkali metal in ammonia paramagnetic ?
Yes
Is brown coloured solution of alkali metal in ammonia paramagnetic ?
No. Its diamagnetic.
How does the complex forming power vary in first group?
Li> Na> K> Rb> Cs
Lithium is softer and has a lower melting point than other alkali metals. True/false?
False. Lithium is harder and has a melting point than other alkali metals.
Lithium can form hydrates but other alkali metals cannot form hydrates. True/false?
True
LiOH on heating gives
Li2O + water
LiNO3 on heating gives
Li2O +NO2 + O2
KNO3 on heating gives
KNO2 + O2
Can hydrogencarbonate of lithium by isolated in solid state?
No
Can hydrogencarbonate of alkali metals other than lithium by isolated in solid state?
Yes
Sylvine is the ore of
Potassium (KCl)
Crude salt contains impurities like MgCl2 and CaCl2 along with NaCl. To remove the impurities, HCl gas is passed. Due to common ion effect impurities precipitate out leaving only NaCl in the solution.
True/false?
False.
Due to common ion effect NaCl precipitate out. Chlorides of calcium and magnesium are more soluble and remain in the solution.
Which process is used for the manufacturing of washing soda?
Solvay process
What is washing soda?
Na2CO3.10H2O
Why can’t solvay process be employed for the manufacture of potassium carbonate?
Because potassium bicarbonate is fairly soluble in water and does not precipitate easily.
What is soda ash?
Na2CO3
What is baking soda?
NaHCO3
Castner Kellner cell is used in the manufacturing of
NaOH
Which electrode does the outer compartment of Castner Kellner cell act as?
Anode
Which electrode does the inner compartment of Castner Kellner cell act as?
Cathode
Which electrode does the mercury of central compartment of Castner Kellner cell act as?
Anode
Which electrode does the mercury of outer compartment of Castner Kellner cell act as?
Cathode
NiSO4 + NaOH ———->
Na2SO4 + Ni(OH)2
Reaction of aluminium hydroxide with excess of sodium hydroxide gives
Na3[Al(OH)6]
Which have stronger metallic bonds- alkali earth metals or alkaline earth metals?
alkaline earth metals
Which have higher melting point- alkali earth metals or alkaline earth metals?
alkaline earth metals
Which colour does magnesium impart to flame?
None
Which has higher melting point- magnesium or calcium?
Calcium
Is MgH2 covalent?
Yes
When alkaline earth metals are burnt in air they form
Oxides and nitrides (MO, M3N2)
BeO reacts with water with evolution of heat to form corresponding hydroxides which are sparingly soluble. True/false?
False.
All alkaline earth metals except BeO reacts with water with evolution of heat to form corresponding hydroxides which are sparingly soluble.
How does solubility of hydroxides of alkaline earth metals vary down the group?
Down the group, solubility increases. BeO and MgO are almost insoluble.
Can hydrogen carbonates of alkaline earth metals be isolated in solid state?
yES
All alkali metals carbonates are unstable and can be kept only in an atmosphere of CO2. True/false.
False.
All alkaline earth metals carbonates are unstable and can be kept only in an atmosphere of CO2.
Are carbonates of alkaline earth metals soluble in water?
No
how does solubility of sulphates of alkaline earth metal vary down the group?
Solubility decreases down the group
Are sulphates of alkaline earth metals stable to heat?
Yes
(NH4)2BeF4 —————>
BeCl2 + CO
BeCl2 is present as a monomer in vapour form above 1200K and as a dimer in vapour form below 1200K. True/false?
True
In general which are more stable to heat- the oxo salts of group 1 or the oxosalts group 2 metals?
Oxosalts of group 1 metals
Beryllium carbide on reaction with water produces
Methane
Magnesium carbide on reaction with water produces
Acetylene
Beryllium can show a coordination number of four. True/false?
True
Which alkaline earth metal(s) form(s) fluoro complex ions in solution?
Beryllium
What is gypsum?
CaSO4.2H2O
CaO + C —————–>
CaC2 +CO
For good quality cement, the ratio of SiO2 to Al2O3 should be
2.5 TO 4
For good quality cement, the ratio of CaO to total oxides of silicon, aluminium and iron should be
2
Why is gypsum added to portland cement?
To regulate the setting time